Ground Water Protection Study

The objectives of the Groundwater Protection Study are to assess groundwater conditions throughout the district, to provide the Highlands with information and tools to support the protection and conservation of groundwater quality and quantity, and to guide future land-use decisions within the Highlands in light of potential climate change impacts.

A Comprehensive Groundwater Study has been underway since September 2007. Golder and Associates is the consultant tasked with the work. Progress has been monitored by the district’s Groundwater Task Force.

Phase 1 Groundwater Protection Study

This phase reviewed available information, including water well records, geological mapping, climate and precipitation data to develop a conceptual model of groundwater flow in theHighlands. Information included stream flow monitoring to assess baseflow at the end of the dry season (this supplements the available background information);

Assigned Hydrogeologic parameters to the bedrock units and developed and calibrated a District-wide numerical hydrogeological model to steady-state (i.e., average annual) conditions model used to conduct water balance analyses to assess the sustainability of current and future groundwater withdrawals, together with the potential impacts of climate change; and

A preliminary groundwater quality and water-level monitoring program was implemented to collect the data needed to assess baseline conditions and seasonal patterns.

The pcompiled a regional contaminant inventory to identify potential sources of contamination in the Highlands. The Highlands was categorized into three types of land use activities:

Park and Rural Residential (P/RR);

Commercial/Industrial (C/I);

and Comprehensive Development (CD);

In each land use category, existing and potential hazards to groundwater quality were identified and relative rankings were assigned to the identified hazards to provide the District with guidance on prioritizing groundwater protection efforts;

Preliminary groundwater protection measures were developed to establish the framework for the groundwater protection measures that were developed during Phase 3 of the Study; and

The groundwater quality and water-level monitoring program was expanded based on the results of both the contaminant inventory and the water balance analyses (Phase 1).